Loud ticking and/or rattling sound when accelerating?

First of all where is the ticking noise coming from? Meaning, the top of the engine or the bottom or the front? When the engine is idling does it make the same noise? Is the oil low?
Sometimes a ticking sound is just a worn out serpentine belt tension pulley or idler pulley. Or it may be a loose or damaged rocker arm, a bad valve spring, a bad oil pump. What is your oil pressure? If your pistons are blown then smoke will billow out the exhaust pipes. Is this happening? If your exhaust manifold is broken the noise will be unmistakably loud as if there was no muffler on the exhaust pipe and your engine will misfire really bad. Is this happening?
Is the check engine light on? When you drive it is there a noticeable loss of power? Did you do a compression test on the engine? If so what were the results?

If there is a check engine light on then there is a trouble code stored in the computer. Have your Tahoe scanned. Autozone or a place like that will do this for free. When they scan the engine let me know what the trouble code is.
However, I do not want to miss lead you or give you false hope; but it sounds like there may be a piston ring problem. When the rings wear out, oil passes by them and burns up during the firing of the piston. This causes a whiteish smoke, and you also can tell by black deposits on your spark plugs. Is there any excessive oil consumption or do you have to add oil frequently?
Unfortunatly a piston ring problem requires that the engine must be rebuilt.

Hi Marie,

We need to start with basically the same info as above. However, if you could get a video of the noise then that will help narrow this down.

I would suggest we start with finding out if the engine has any metal in the oil.

Let's drain the oil into a clean pan and look in the bottom of the pan for any metallic shiny pieces. It will look like glitter in the bottom of the oil pan. You can also cut the filter apart if you want to but that is not needed.

https://www.2carpros.com/articles/how-to-change-engine-oil-and-filter

Next we need put oil back in and drive the vehicle. I don't expect this will fix the issue but clearly if we start to get some of the acceleration power back then we are on the right track.

The lack of power and noise when accelerating normally points to a motor that is locking up but there could be other issues.

Does this ticking noise happen all the time or does it stop when you let off the gas? What about when just sitting at idle, does it make the noise then or do you have to be moving?

Let's start with this and see if you can get the video and check the oil and we can go from there. Thanks